Radiators are an integral part of engines. They are used to transfer heat from a coolant liquid to the atmosphere, cooling the coolant liquid and allowing its re-circulation.
A typical known radiator assembly is illustrated in FIG. 1. The assembly comprises a radiator core connected to a top tank 2. A header tank 4 (also referred to as an expansion tank) is connected to the top tank 2 by two separate connections. A first connection 6 is provided to allow coolant liquid to flow from the header tank 4 into the top tank 2 and a second connection 8 is provided to allow any gas present in the top tank 2 to escape to the header tank 4.
Typically the two connections 6 and 8 are achieved with two flexible hoses, one between connector 6 and its counterpart and one between connector 8 and its counterpart. Clips are usually required to ensure that the flexible hose is securely attached to the connector.
When used in a vertical configuration, the top tank 2 is completely filled with coolant liquid and the header tank 4 is partially filled with coolant liquid. Thus, there exists an air space in the header tank to accommodate changes in the volume of coolant liquid as its temperature alters during operation of the radiator assembly.
Assemblies of this type use two ports because this results in more efficient operation, particularly during an operation to fill the assembly with coolant liquid. If only a single port is provided for both filling and ventilation then, during filling of the tank, any air escaping from the top tank 2 must flow against the cooling liquid flowing in through the single port. This inhibits smooth filling and venting. The two connector assembly allows a smoother flow since there is a port dedicated for liquid and a port dedicated for ventilation.
A disadvantage of the two port assembly is that the overall complexity is increased due to the need to have two connections.